As the number of Linux kernel contributors continues to grow, core developers are finding themselves mostly managing and checking, not coding, said Greg Kroah-Hartman, maintainer of USB and PCI support in Linux and co-author of Linux Device Drivers, in a talk at the Linux Symposium in Ottawa Thursday. In the latest kernel release, the most active 30 developers authored only 30% of the changes, while two years ago, the top 20 developers did 80% of the changes, he said.